The present invention relates to vehicle seats, and particularly relates to vehicle seats to reduce the impact at the time of a rear-end collision.
In general, when a vehicle such as an automobile experiences a rear-end collision by being rear-ended, a large impact when traveling in reverse, or the like, there is a risk that the head region of an occupant sitting in a seat in the vehicle will snap backwards suddenly due to inertia force, resulting in an impact on the neck region.
For this reason, vehicle seats in automobiles and the like have conventionally included headrests in the upper area of the seat backs that support the heads of occupants from behind in order to protect the head regions, neck regions, and the like, of occupants from impacts caused by rear-end collisions, thereby reducing impact on the neck regions of the occupants.
However, simply providing a headrest cannot reduce impacts on the body, and furthermore, if the gap between the head region of the occupant and the headrest cannot quickly be reduced at the time of a rear-end collision, there may be the cases where the impact upon the neck region cannot sufficiently be reduced.
In order to solve this problem, a technique in which the headrest is caused to move forward at the time of a rear-end collision due to the backward moving load of the occupant, thus supporting the head region of the occupant and reducing the impact on the neck region, has been proposed (for example, see Japanese Patent Application Publication No. 2003-341402 (“the '402 Publication”)).
In addition, a technique in which, in a vehicle seat provided with a seat back that supports a seat back cushion using a seat back frame, the area of the seat back that makes contact with the back of the occupant at the time of a rear-end collision has a lower spring coefficient and a higher damping coefficient than those of the other areas, is known (for example, see Japanese Patent Application Publication No. 2005-028956 (“the '956 Publication”)).
Furthermore, a vehicle seat has been proposed in which, in a backrest that includes a headrest, a mobile frame having a spring member that supports a cushion member is attached to a fixed frame on the top of which the headrest is mounted so that the upper portion of the mobile frame rotates backward along the lower portion of the mobile frame; furthermore, a spring that supports a normal seating load but allows the mobile frame to move backward when an impact load greater than or equal to a predetermined load is exerted thereon is provided between the fixed frame and the mobile frame (for example, see Japanese Patent Application Publication No. 2000-272395 (“the '395 Publication”)).
Although both of the techniques disclosed in the '402 and '956 Publications soften the impact on an occupant, the technique disclosed in the '402 Publication receives the backward movement of the chest area of the occupant with a pressure receiving member at the time of a rear-end collision, and causes the headrest to move forward along with the backward movement of the pressure receiving member. With such a technique, it is necessary to provide a separate movement mechanism for the headrest in order to allow the tandem movement with the headrest, which complicates the mechanism and increases the cost thereof. Furthermore, because it is necessary to provide a mobile portion in the seat back frame in order to move the headrest, it is also necessary to prevent a resulting rigidity degradation of the structure. Therefore, an increased rigidity beyond what is normally required is necessary.
The technique disclosed in the '956 Publication increases the backward movement of the upper body and decreases the relative amount of movement between the head region and the back region by reducing the spring coefficient of the area that makes contact with the back region of the seat back (the “chest region” in the '956 Publication), and, by increasing the damping coefficient by way of a cushion of low rebound resilience, reduces the shearing force that acts on the neck region by suppressing rebounding of the upper body and reducing the relative speed between the head region and the back region.
However, with a technique that reduces the spring coefficient, a technique that employs a cushion of low rebound resilience, or the like, there has been a problem in that the amount by which the body sinks toward the back of the vehicle (in other words, the amount of movement) cannot be increased.
Furthermore, the technique disclosed in the '395 Publication simply sets the elastic force of the spring relative to the impact load, and thus the operational load at which a central support portion moves backward can reliably be predicted, ensuring that that portion moves backward without fail. This technique thus has an advantage of ensured operations.
However, with the technique disclosed in the '395 Publication, the fixed frame and the mobile frame are fixed at their lower portions using an attachment shaft, and thus there is a quite small movement of the mobile frame allowed relative to the fixed frame in the vicinity of the lower areas thereof. So, there is a problem in that the entire body of a seated occupant cannot be caused to sink toward the back of the vehicle. Furthermore, the spring disclosed in the '395 Publication experiences reaction force increase along with an increase of the amount of movement, which disturbs the movement. Furthermore, the range of mobility between the fixed frame and the mobile frame is extremely limited, and there has thus been a problem in that it is difficult to ensure a movement amount that allows a high degree of sinking. Furthermore, because the mobile frame is used, the overall size of the apparatus increases and achieving a lighter weight is difficult.
Accordingly, in vehicle seats, it is desirable to increase the amount by which the entire body of an occupant sinks into the seat at the time of a rear-end collision, and it is particularly desirable to increase the amount of movement of the lower back region.
Furthermore, it is desirable for vehicle seats to cause the entire body of an occupant to sink therein at the time of a rear-end collision with a high load transfer efficiency. In particular, because the seat back tilts backward at the time of a rear-end collision, it is desirable, while the movement of the seat back is considered, to make use of the load from the occupant in order to ensure that a supporting member (a pressure receiving member) supporting the body of the occupant has a sufficient amount of movement.
It is an object herein to provide a vehicle seat that, using a simple configuration that is independent from a headrest, increases the amount of sinking (movement) of the entire body of a seated occupant, including the lower back region of the occupant, toward the rear of the vehicle at the time of a rear-end collision, and effectively reduces the impact on the occupant at the time of a rear-end collision.
In addition, it is another object herein to provide a vehicle seat that, using a configuration that does not require rigidity beyond what is normally required, with a suppressed number of components, a smaller size and lighter weight, and a low cost, effectively reduces the impact on the neck region and the like of an occupant by causing the entire body of the occupant to sink toward the rear of the vehicle at the time of a rear-end collision.
It is yet another object herein to provide a vehicle seat that, while the backward tilting movement of a seat back at the time of a rear-end collision is took into consideration, increases the amount by which the entire body of an occupant sinks, including the amount of movement of the lower back region of the occupant, by making use of the load from an occupant in order to ensure that a supporting member has a sufficient amount of movement, and effectively reduces the impact on the neck region and the like of the occupant.
It is still another object herein to provide a vehicle seat that effectively provides side portions having rigidity with impact reduction members that move independently from headrests in order to reduce the impact on the neck region and the like of an occupant at the time of a rear-end collision, and prevents interference with other provided members.
The problems described above are solved by a vehicle seat including: a seat back frame including at least side portions located on both sides of the seat back frame and an upper portion disposed in an upper area of the seat back frame; a headrest disposed in an upper area of the seat back frame; a supporting member that supports the body of an occupant, the supporting member moving independently from the headrest; and an impact reduction member that is disposed in at least one of the side portions of the seat back frame, is linked to the supporting member, and is movable independently from the headrest under a predetermined impact load, in which an entirety of the supporting member moves toward the rear of the vehicle under a predetermined impact load that is greater than a normal seating load.
In this manner, the entirety of the supporting member that supports the occupant and moves independently from the headrest moves toward the rear of the vehicle under a predetermined impact load that is greater than a normal seating load, and thus the entire body of the seated occupant sinks toward the rear of the vehicle without requiring a mechanism or the like for transmitting the load to the headrest. In other words, the entirety of the seat back sinks without, as in the case of the techniques according to the prior art in which a mobile frame moves backward along a rotation shaft, the problem of the insufficient amount of sinking or the problem of the lack of sinking in the vicinity of the rotation shaft.
Furthermore, because the entirety of seat back sinks, the body of the occupant moves toward the rear of the vehicle in a state where the seated posture of the body of the occupant is maintained. This makes it possible for the head region of the occupant to approach the headrest and make contact with the headrest in a state where the seated posture of the occupant is maintained, without providing a mechanism linked with the headrest for causing the headrest to move forward. Accordingly, impacts exerted on the head region or the neck region at the time of a rear-end collision can effectively be reduced.
In an embodiment, the supporting member is linked, by a deformable coupling member, to each of the side portions in at least an upper portion and a lower portion of the supporting member, and the lower part is a location that corresponds to the lower back region of the occupant.
In this manner, the side portions on both sides are linked in at least two locations above and below the supporting member by the deformable coupling member, and the lower part is a location that corresponds to the lower back region of the occupant. Accordingly, the lower back region that receives the greatest load when the occupant is seated has a large amount of sinking (movement), and thus the head region of the occupant can make contact with the headrest without fail in a state where the seated posture of the occupant is maintained. Accordingly, impacts on the neck region of the occupant are reduced by supporting the head region of the occupant without movement along with that of the headrest.
In an embodiment, the supporting member moves more in the lower part than the upper part under the predetermined impact load.
In this manner, the lower part moves more than the upper part of the supporting member that is linked to the seat back frame in two locations. Therefore, it facilitates to ensure a larger amount of movement of the lower back region, which receives a large load, and a larger amount of movement is ensured for the entire body of the occupant.
In an embodiment, a linking portion between the impact reduction member and the supporting member move upward under the predetermined impact load.
In this manner, the linking portion between the impact reduction member and the supporting member moves upward and the entirety of the supporting member moves toward the rear of the vehicle. Accordingly, even if the seat back tilts backward due to a rear-end collision, the supporting member is moved backward along with the tilting movement. Thus, a sufficient amount of sinking of the entire body of the occupant is ensured at the time of a rear-end collision with a high load transfer efficiency.
In an embodiment, a linking portion between the impact reduction member and the supporting member may move in the horizontal direction and then move upward under the predetermined impact load.
In this manner, the linking portion between the impact reduction member and the supporting member moves in the horizontal direction and then moves upward, and the entirety of the supporting member moves toward the rear of the vehicle. Accordingly, it is possible to ensure a sufficient amount of movement of the supporting member by making effective use of the load from the occupant, while the tilting movement of the seat back in the backward direction at the time of a rear-end collision is took into consideration.
In an embodiment, a linking portion between the impact reduction member and the supporting member may move downward and then move upward under the predetermined impact load.
In this manner, the linking portion between the impact reduction member and the supporting member moves downward and then moves upward, so that the entirety of the supporting member moves toward the rear of the vehicle. The downward movement can ensure the stability of the seating of the occupant by suppressing unstable movement at the time of the initial movement state. Further, the linking portion moves in the upward direction along with the backward tilting of the seat back, making it possible to increase the load transfer efficiency.
In an embodiment, a linking portion between the impact reduction member and the supporting member move upward under the predetermined impact load after a load received by the supporting member from the occupant has passed a maximum load point.
In this manner, the linking portion between the impact reduction member and the supporting member moves upward after the supporting member exceeds the maximum load point received from the occupant, and the entirety of the supporting member moves toward the rear of the vehicle. Accordingly, efficient movement is achieved even in lower load regions that are below the maximum load point, and effective sinking is ensured even in the case where the load decreases.
In an embodiment, the seat back frame includes a lower portion disposed in a lower area, and the impact reduction member is disposed within a range enclosed by the seat back frame.
In this manner, because the impact reduction member is disposed within a range enclosed by the seat back frame, the portion of the seat back corresponding to the lower- to mid-back region of the occupant is moved significantly backward when an impact has occurred, without interference with the various elements disposed on the outside of the seat back frame. This makes it possible to cause the occupant to sink to a sufficient extent.
In an embodiment, the impact reduction member is disposed in a range that is below the upper end of the supporting member.
This makes it possible to efficiently transmit the load from the supporting member that supports the body of the occupant to the impact reduction member, the portion of the seat back corresponding to the lower- to mid-back region of the occupant is moved significantly backward when an impact has occurred, and thus to cause the occupant to sink to a sufficient extent.
In an embodiment, the seat back frame includes a pipe portion that spans across the side portions and the upper portion, and a reclining mechanism has a rotation shaft, and the impact reduction member is disposed between the lower end of the pipe portion and the rotation shaft of the reclining mechanism.
With this configuration, the impact reduction member can effectively be disposed in the side portions having rigidity, and the impact reduction member is disposed in a position where the amount of sinking is large, so that the load can efficiently be transmitted. Accordingly, the portion of the seat back corresponding to the lower- to mid-back of the occupant is moved significantly backward when an impact has occurred, and it makes possible to cause the occupant to sink to a sufficient extent.
In an embodiment, a disposal range for an airbag apparatus is formed in the side portions of the seat back frame, and the impact reduction member is disposed between the upper end and the lower end of the disposal range for an airbag apparatus.
With this configuration, interference with other disposed elements is prevented, and the impact reduction member is disposed using the small space more effectively.
In an embodiment, a recess portion is formed in the supporting member in an area that opposes the seat back frame, and the impact reduction member is disposed in a location that opposes the recess portion of the supporting member.
With this configuration, because the recess portion is provided, the impact reduction member is checkable when and after it is assembled and when the skin material is opened.
In an embodiment, the impact reduction member is disposed in the upper part in at least one of the side portions, and is rotatable or movable under a predetermined impact load. By providing the impact reduction member in the upper part of the side portions in this manner, a sufficient amount of sinking is ensured for the upper part. Thus, the impact reduction member moves smoothly and can sink to a large extent at the time of a rear-end collision.
In an embodiment, the impact reduction member is disposed in the upper part and the lower part in at least one of the side portions, and is rotatable or movable under a predetermined impact load. By providing the impact reduction member in the upper part and the lower part in this manner, the sinking caused by an impact load can smoothly be carried out.
In an embodiment, by making the upper part smaller than the lower part in the side portions, the impact reduction member is disposed in the small space of the upper part without fail.
With an embodiment of the vehicle seat described above, the entire body of the seated occupant sinks toward the rear of the vehicle without requiring a mechanism or the like for transmitting the load to the headrest. In other words, the entirety of the seat back sinks without, as in the case of the techniques according to the prior art in which a mobile frame moves backward along a rotation shaft, the problem of the insufficient amount of sinking or the problem of the lack of sinking in the vicinity of the rotation shaft. This makes it possible to effectively reduce impacts exerted on the head region or the neck region at the time of a rear-end collision.
With an embodiment of the vehicle seat described above, the lower back region that receives the largest load when the occupant is seated has a large amount of sinking (movement), and thus the head region of the occupant can make contact with the headrest without fail while the seated posture of the occupant is maintained.
With an embodiment of the vehicle seat described above, the lower part moves more than the upper part of the supporting member that is linked to the seat back frame in two locations. It is therefore easier to ensure a larger amount of movement for the lower back region of the occupant, and a larger amount of movement of the entire body of the occupant is ensured as a result.
With an embodiment of the vehicle seat described above, the linking portion between the impact reduction member and the supporting member moves upward and the entirety of the supporting member moves toward the rear of the vehicle. Accordingly, even if the seat back tilts backward due to a rear-end collision, the supporting member moves along with the tilting direction. This makes it possible to ensure a large amount of sinking for the entire body of the occupant, which provides a high load transfer efficiency, at the time of a rear-end collision.
With an embodiment of the vehicle seat described above, the linking portion between the impact reduction member and the supporting member initially moves in the horizontal direction and then moves upward. Accordingly, it is possible to ensure a sufficient amount of movement of the supporting member by making effective use of the load from the occupant, while the tilting movement of the seat back in the backward direction at the time of a rear-end collision is took into consideration.
With an embodiment of the vehicle seat described above, the linking portion between the impact reduction member and the supporting member moves downward, to ensure the stability of the seating of the occupant during the initial movement state. The linking portion moves in the upward direction along with the backward tilting of the seat back, and this makes it possible to increase the load transfer efficiency.
With an embodiment of the vehicle seat described above, the impact reduction member can efficiently move even in lower load regions that are below the maximum load point. Thus, sinking can effectively be ensured even in the case where the load decreases.
With an embodiment of the vehicle seat described above, the portion of the seat back corresponding to the lower- to mid-back region of the occupant moves significantly backward when an impact has occurred, without interference with the various elements disposed on the outside of the seat back frame. This makes it possible to cause the occupant to sink to a sufficient extent.
With an embodiment of the vehicle seat described above, it is possible to efficiently transmit the load from the supporting member that supports the body of the occupant to the impact reduction member, and thus the portion of the seat back corresponding to the lower- to mid-back region of the occupant moves significantly backward when an impact has occurred. This makes it possible to cause the occupant to sink to a sufficient extent.
With an embodiment of the vehicle seat described above, the impact reduction member is disposed in a position where the amount of sinking is large, and thus it is possible to efficiently transmit the load. Accordingly, the portion of the seat back corresponding to the lower- to mid-back of the occupant moves significantly backward when an impact has occurred. This makes it possible to cause the occupant to sink to a sufficient extent.
With an embodiment of the vehicle seat described above, interference with other disposed elements is prevented, and the impact reduction member is disposed using the small space more effectively.
With an embodiment of the vehicle seat described above, the impact reduction member can be checked when and after the seat back is assembled and when the skin material is opened.
With an embodiment of the vehicle seat described above, by providing the impact reduction member in the upper part of the side portions, a sufficient amount of sinking for the upper part is ensured. Thus, the impact reduction member moves smoothly and can sink to a large extent at the time of a rear-end collision.
With an embodiment of the vehicle seat described above, by providing the impact reduction member in the upper part and the lower part, the sinking caused by an impact load can smoothly be carried out.
With an embodiment of the vehicle seat described above, the impact reduction member is disposed in the small space of the upper part without fail.
As described thus far, because the entirety of the seat back sinks, the body of the occupant moves toward the rear of the vehicle while the seated posture of the body of the occupant is maintained. Thus, the head region of the occupant can make contact with the headrest in a state where the seated posture of the occupant is maintained, without providing a mechanism linked with the headrest for causing the headrest to move forward. This makes it possible to effectively reduce impacts on the neck region and the like.
Accordingly, it is possible to provide a vehicle seat that, with a simple configuration that is independent from a headrest, increases the amount of sinking (movement) of the entire body of a seated occupant including the lower back region of the occupant into the rear of the vehicle at the time of a rear-end collision, and effectively reduces the impact on the occupant at the time of a rear-end collision.
In addition, it is possible to provide a vehicle seat that, using a configuration that does not require rigidity beyond what is normally required, with a suppressed number of components, a smaller size and lighter weight, and a low cost, effectively reduces the impact on the neck region and the like of an occupant by causing the entire body of the occupant to sink into the rear of the vehicle at the time of a rear-end collision.
Furthermore, while the backward tilting movement of a seat back at the time of a rear-end collision is took into consideration, by efficiently making use of the load from an occupant, it is possible to increase the amount by which the overall body of an occupant sinks, including the amount of movement of the lower back region of the occupant, in order to ensure that a supporting member has a sufficient amount of movement, and it is possible to effectively reduce the impact on the neck region and the like of the occupant.
Finally, it is possible to effectively provide side portions having rigidity with impact reduction members that move independently from headrests, in order to reduce the impact on the neck region and the like of an occupant at the time of a rear-end collision, and it is possible to prevent interference with other members that are provided.